J.K. Rowling had plans to kill off Arthur Weasley by the end of the Harry Potter series. Actor Mark Williams portrayed the Weasley family patriarch for the duration of the series, serving as one of the few admirable father figures in the story. Despite Rowling's original intent in regards to Arthur's fate, the character survived the events of the final installment, and he remains alive and well in the fictional universe.
After making his debut in Harry Potter and the Chamber of Secrets, Arthur served as a prominent figure throughout the series. Before becoming the father of seven children, Arthur was a student at Hogwarts as a member of Gryffindor. Upon graduating, he married and took a job at the Ministry of Magic in the Misuse of Muggle Artefacts Office. Arthur, along with his wife and kids lived in the Burrow, a magical residence that became a second home to Harry Potter. When the Second Wizarding War commenced, Arthur joined the Order of the Phoenix and bravely fought during the Battle of Hogwarts.
As a member of the Order of the Phoenix, Arthur agreed to protect the Hall of Prophecy at the Ministry. One night while on guard, Arthur was attacked by Nagini at the command of Lord Voldemort. Harry acquired a vision of the events based on his connection to Voldemort, allowing the young wizard to alert of the attack. While Arthur was saved before he was gravely injured, Rowling contemplated killing off the figure in Harry Potter and the Order of the Phoenix. The author would go on to consider Arthur's demise once again in the final book, Harry Potter and the Deathly Hallows, which would have occurred in the eighth and final film. Instead, Rowling went in a different direction, but she has explained her reasoning on several occasions.
Not only did Rowling worry about killing Arthur based on his story potential, but she also realized how much it would affect Ron Weasley. As one of the young lead figures of the Harry Potterfranchise, Ron was often at the front and center of the plot. According to Rowling's Carnegie Hall reveals shortly after finishing the novels, the author feared that killing off Mr. Weasley would have been detrimental to his youngest son's arc. Ron was a source of comic relief throughout the franchise, but losing his dad would have greatly altered his demeanor. That situation was already played out with Harry, so she decided against the idea.
The notion of killing Arthur returned during the end of Harry Potter, specifically during the Battle of Hogwarts. While some might assume that she axed the idea based on Fred Weasley's tragic death, his son's demise didn't factor into Arthur's fate. The author always had the intention to eliminate respectable parents by the end of the series. To compensate for Arthur's survival, Rowling chose to kill off Remus Lupin and Nymphadora Tonks, who just had a son months before the Battle of Hogwarts. Following the events of Harry Potter, Arthur went on to assist with Muggle Rights while living happily as a husband, father, and grandfather.